ajit257 wrote:
thanks a ton guys...ok so statement makes sense, i got that right but my confusion was over statement 2
stmt 2 : it gives us the mean. We already know the that set is set of consecutive even numbers so we know it is evenly distributed so why cant we calculate the SD.
Can someone clarify this.
380,382,384. Mean=382. Standard deviation: 2
378,380,382,384,386. Mean=382: Standard deviation: Somewhere between 2 and 4
376,378,380,382,384,386,388; Mean=382: Standard deviation: Somewhere between 4 and 6
Even though the even numbers are symmetrically distributed about the mean, with every inclusion of a pair of numbers, the standard deviation will gradually increase.
380,382,384:
Here there are just two numbers on both sides of 382. The deviation of 380 from the mean 382 is 2; the deviation of 384 from the mean 382 is also 2, thus the standard deviation is 2.
378,380,382,384,386
Here there are 5 numbers.
382 is the mean.
The deviation of 380 from the mean 382 is 2; the deviation of 384 from the mean 382 is also 2;
But,
The deviation of 378 from the mean 382 is 4; the deviation of 384 from the mean 386 is also 4;
Thus the standard deviation will be somewhere between 2 and 4.
Also, as per the rule, the standard deviation increases with increase in the Range of the set.
380,382,384. Range=4
378,380,382,384,386. Range=8
376,378,380,382,384,386,388. Range=12